A holder for a beverage container including a container support platform having a central axis, and a series of container contact elements disposed around the central axis for exerting positioning forces on side surfaces of the container. Each container contact element contains a liquid core material that transitions to a near-solid state when subjected to a magnetic field. Magnetic mechanisms are provided in the holder for generating one or more magnetic fields, that have the result of rigidifying the container contact elements to conform to a range of different container sizes and shapes. The magnetic mechanisms can be electro-magnets or permanent magnets.